Abstract: The sexual maturity of beef cattle is regulated by the hypothalamus-pituitary-ovary（HPO） axis, but its specific mechanism is not clear. To explore the HPO-axis reproduction related genes and regulatory mechanisms,the hypothalamus, pituitary and ovary of adult Angus cattle（30 months of age） were studied by applying high-throughput transcriptome RNA-seq techniques. The results showed that the HPO had a total of 18 179 genes annotated in GO（Gene Ontology）, 37 158 genes annotated in KEGG（Kyoto Encyclopedia of Genes and Genome）, or 36 645 genes annotated in KOG（KEGG Ortholog database）, respectively. GO analysis revealed that the HPO enriched eight kinds of reproduction related functions, mainly were fertilization, reproduction process of single tissue, embryonic development in uterus, and estrogen response. KEGG analysis found that the HPO enriched 300 signaling pathways（SPs）, mainly cancer SP and phosphatidylinositol 3 kinase protein kinase（PI3 K-Akt） SP. There were a total of 16 SPs related to reproduction, mainly Notch SP, Neurotrophin SP, Mammalian target of rapamycin（mTOR） SP, and Vascular endothelial growth factor（VEGF） SP. It provided a scientific basis for future beef cattle improvement of reproductive performance, molecular breeding and peer reference.